This invention relates to an electronic component cooling apparatus, and more particularly to an electronic component cooling apparatus adapted to cool an electronic component while being received in a receiving housing of an electronic appliance.
Japanese Patent Application Laid-Open Publications Nos. 231940/1990 (2-231940) and 231941/1990 (2-231941) each disclose an air fan constructed so as to flow or feed air in a radial direction thereof perpendicular to an axial direction thereof by means of an axial fan. The air fan is generally called a radial fan in the art. An axial fan includes an impeller mounted on a revolving shaft of a motor. The impeller is provided with a plurality of blades and constructed so as to suck in air on one of both sides defined in an axial direction of a revolving shaft of the motor and guide it toward the other side. Also, the impeller is arranged in a cylindrical cavity which is defined in a casing by a peripheral wall of the casing. The axial fan exhibits characteristics capable of increasing the amount of air fed while keeping a pressure at a reduced level. The radial fan was developed utilizing such advantageous characteristics of the axial fan. Thus, the radial fan exhibits characteristics capable of increasing the amount of air fed while being reduced in thickness or depth thereof as compared with a cross-flow fan or a cirrocco fan and reducing noise as compared with a cirrocco fan.
The conventional radial fan described above is so constructed that a cavity in which an impeller is received is closed at one end thereof with a wall and provided with a lateral outlet or discharge port, which is formed by removing a part of a peripheral wall of a casing. The lateral discharge port is provided so as to thoroughly extend from one end of the cavity to the other end thereof, so that blades of the impeller each are fully exposed from the lateral discharge port of the casing when it faces the port during of the impeller.
U.S. Pat. Nos. 5,421,402, 5,452,181 and 5,484,013, Japanese Utility Model Publication No. 15982/1991 (3-15982), and Japanese Patent Application Laid-Open Publication No. 111302/1995 (corres. to U.S. Ser. No. 08/208,125) each disclose an electronic component cooling apparatus which is constructed so as to cool a heat sink mounted thereon with an electronic component such as a CPU or the like by means of an axial fan.
The inventors manufactured an electronic component cooling apparatus including the conventional radial fan constructed as described above utilizing the axial fan and made an experiment on the cooling apparatus thus manufactured. As a result, it was found that the radial fan causes the amount of air discharged from the lateral discharge port to be less than expected.
Also, when an electronic component cooling apparatus including the conventional radial fan is received in a receiving casing of an electronic appliance decreased in thickness or depth, it causes the amount of air fed to be excessively decreased or rendered substantially zero.